A semiconductor device such as an LSI (Large Scale Integrated circuit) or a MOS (Metal Oxide Semiconductor) transistor is manufactured by performing various processes such as etching, CVD (Chemical Vapor Deposition) and sputtering on a semiconductor substrate (wafer) as a processing target substrate. A processing method using plasma as an energy source, i.e., plasma etching, plasma CVD or plasma sputtering may be used to perform the etching, the CVD or the sputtering process.
Here, a microwave plasma processing apparatus using microwave to generate plasma is described in WO2009/101927A1 (Patent Document 1). In this microwave plasma processing apparatus of Patent Document 1, a ceiling plate (dielectric window) that transmits microwave is provided. In order to uniformly transmit microwave in a circumferential direction of the ceiling plate, a recess is formed on a surface of the ceiling plate (dielectric window) at the side where plasma is generated. The recess resonantly absorbs the microwave at side surfaces thereof and allows the microwave to propagate therein in a single mode.    Patent Document 1: WO2009/101927A1